Data storage devices can be used to store and retrieve user data in a fast and effective manner. Some data storage devices utilize a semiconductor array of solid-state memory cells to store data. The memory cells can be volatile or non-volatile. Some non-volatile memory cells can be provided with a 1T1R configuration with a single transistor (“T”) and a single programmable resistive memory element (“R”).
The resistive memory element is programmable to different resistive states through the application of write currents to the memory cell, and these different resistive states can be used to denote different logical states (e.g., logical 0, 1, 10, etc.). The programmed state of the resistive memory element can be sensed by application of a read current to the memory cell, and a comparison of the voltage drop across the cell with a reference voltage using a sense amplifier. The memory cell transistor serves as a switching device to facilitate access to the memory cell during write and read operations, and to decouple the memory cell from adjacent cells at other times.
A number of resistive memory element (RME) constructions are known, including without limitation magnetic random access memory (MRAM), spin-torque transfer random access memory (STRAM), resistive random access memory (RRAM), phase change random access memory (PCRAM), and programmable metallic cells (PMCs). While operable, a limitation with these and other RME constructions relates to difficulties in reliably sensing the different resistive states to which the cells are programmed. Significant portions of the available semiconductor area may be allocated for circuitry used during read and write operations. This increased overhead can limit overall data storage densities for a given semiconductor size.